1. Field of the Invention
The present invention relates to the field of liquid crystal display (LCD), and in particular to a gate driver on array (GOA) circuit for in-cell type touch display panel.
2. The Related Arts
The gate driver on array (GOA) technology is the array substrate column drive technology, by using the thin film transistor (TFT) liquid crystal display (LCD) array processor to manufacture the gate scan driver circuit on the TFT array substrate to realize the column-by-column scan driving. The GOA technology has the advantages of low manufacture cost and the ability to realize narrow-border panels, and is used by many types of displays. GOA circuit has two basic functions: first, to output scan driving signal to drive the gate line in the panel to turn on the TFT in the display area so as to charge the pixels; and the second is the shift bit saving; when the N-th scan driving signal is outputted, the clock control is used to perform outputting the (N+1)-th scan driving signal, and so on.
The embedded touch technology is to integrate the touch panel with the liquid crystal (LC) panel, and embed the function of the touch panel to the LC panel so that the LC panel can both display and sense the touch to input. As the display technology rapidly grows, the touch panel is widely accepted and used, such as, smart phone, tablet, and so on.
The current embedded technology can be categorized in two types. The first type is the on-cell type and the other is in-cell type. The driving manner of the in-cell type touch panel is time-division driving, i.e., the display driving and the touch signal driving are separately transmitted.
The in-cell type touch panel usually needs GOA circuit to have the all-gate-on function of raising all the scan driving signals for each stage to a high level during the black screen duration to clear the residual voltage in each pixel. However, the all-gate-on function may not stay in effecting in the current single-type GOA circuit.
The in-cell type touch panel also needs the GOA circuit to have the signal stop (interrupt) function; that is, when the GOA circuit operates normally, the ability to simultaneously turn off the scan driving signals of all GOA stages; then, the panel executes the touch detection. After the interruption, the GOA circuit must return to normal driving function. The risk of electricity leakage exists in the current single-type GOA circuit when performing signal stop.